Six questions about: VX, the chemical WMD that killed Kim Jong-nam

Khalid said investigators discovered the powerful neuro-toxin, classified by the United Nations as a weapon of mass destruction, on swabs taken from the eyes and face of the former heir to the late North Korean dictator Kim Jong-il.
The incident may possibly be only the second recorded use of the chemical weapon for assassination globally, adding to the already surreal nature of the incident that has intrigued Malaysia and the rest of the world.

Perhaps the last time so many people talked about VX was when it fictionally threatened San Francisco in the 1996 Michael Bay blockbuster The Rock starring Sean Connery and Nicholas Cage — albeit with copious artistic licence.

If anything, the revelation has unearthed more questions to be answered amid intense pressure from North Korea, but here is what we know so far:

1. What exactly is VX?

VX does not occur naturally in nature. Like many weapons, the nerve agent was man-made.

VX has no other use except as a chemical weapon. The compounds that would later form the deadly V-series agents were discovered by chemist Ranajit Ghosh in 1950s as potential pesticide. One of the compounds was even marketed under the brand name Amiton, before it was recalled for being too toxic.

The compounds’ potency did not go unnoticed by the British Armed Forces, who in 1952 developed them further at Porton Down in Wiltshire, its secret weapons research facility.

There, the VX was born — its name stood for “venomous agent X”.

Its full name is S-2-diisopropylamino-ethylmethylphosphonothioate: a clear, amber-coloured, oily liquid.

2. Where has VX been used before?

The only other recorded use of VX for assassination was by Japanese Doomsday cult Aum Shinrikyo on December 1994 — the same group responsible for the Tokyo subway Sarin gas attack that killed 12, injured 50 and affected thousands others.

One of its members had reportedly synthesised 100g to 200g of VX to attack three people by sprinkling VX on their necks. One of the victims, Tadahiro Hamaguchi, collapsed into a deep coma — and died 10 days later.

VX is also believed to have been used in warfare, including in the Iran-Iraq War in the 1980s.

3. Why is VX so deadly?

The United States Centers for Disease Control and Prevention (CDC) states that VX is slow to evaporate — ”about as slowly as motor oil”. It is also tasteless and odourless, adding to its stealthiness.

It is the most potent of all nerve agents, and much more toxic than sarin when it enters the body through the skin.

Its median lethal dose, also known as LD50, for humans is estimated to be as low as 10mg through skin contact.

“All the nerve agents cause their toxic effects by preventing the proper operation of an enzyme that acts as the body’s ‘off switch’ for glands and muscles. Without an ‘off switch’, the glands and muscles are constantly being stimulated. They may tire and no longer be able to sustain breathing function,” the CDC said.

Symptoms of VX poisoning include shortness of breath and tightness in the chest, which can be confused for cardiac arrest.

Exposure to a large dose of VX can cause convulsions, loss of consciousness, paralysis and respiratory failure possibly leading to death.

4. When does VX kill its victim?

VX is highly persistent and pose a long-term threat, lasting for days on objects it has come in contact with, and in cold conditions can last for months. It also breaks down slowly in body, leading to cumulative effect if victim is repeatedly exposed to it.

Poisoning by VX depends on exposure, but symptoms will appear within a few seconds after exposed to VX in vapour form, or within a few minutes to up to 18 hours in liquid form.

The two women suspects were said to have wiped a liquid on Jong-nam’s face, who had later sought help from airport staff but died on the way to the hospital.

5. How was the VX administered against Kim?

In warfare, VX is delivered by artillery shells, bombs and landmines, also using aircraft fitted with spray equipment, according to American news outfit ABC.

However, VX is highly lethal when someone comes into direct contact with it. CDC says even a tiny drop of it on the skin can cause sweating and muscle twitching.

Pyongyang has since disputed Malaysian police’s explanation, asking how the two women were still alive when they had handled the substance with their bare hands.

According to CDC, mild or moderately exposed people usually recover completely from VX contamination. Any skin in contact can also be cleaned quickly as simply as using large amount of water and soap.

However, it is also possible that the VX was delivered through a binary weapon — where the toxin is delivered through two separate precursors that are less lethal than the final combined agent.

VX is available in binary form known as VX2, according to the Handbook of Chemical and Biological Warfare Agents. It is formed by mixing O-(2-diisopropylaminoethyl) O′-ethyl methylphosphonite (also known as Agent QL) with elemental sulfur (Agent NE).

6. Who has stockpiles of VX?

After developing VX, the United Kingdom phased out its chemical warfare research and had traded VX technology with the United States for information on thermonuclear weapons in 1958.

The US had mass-produced VX at its Newport Chemical Depot in 1961, before agreeing to destroy its stockpile of aging chemical weapons to ratify the United Nations International Chemical Weapons Convention treaty signed in 1993.

Even since 1969, the US had started disposing of its VX stockpile by sinking ships filled with it in the middle of oceans, incineration, and chemical neutralisation. The remaining 523 tonnes of VX and sarin gas the US still possess is due to be destroyed by its controversial Blue Grass Chemical Agent-Destruction Pilot Plant in Kentucky, which is still yet to be completed.

Other countries that have been reported possessing VX stockpile included Russia and Syria.

Police have so far arrested four people including three foreigners over the killing, while North Korea continues to accuse Malaysia of conspiracy over the latter’s investigation into Jong-nam’s death.

Today’s revelation suggests that North Korea was already aware of what toxin was used in the deadly attack.